20019817 has 2 divisors, whose sum is σ = 20019818. Its totient is φ = 20019816.

The previous prime is 20019781. The next prime is 20019827. The reversal of 20019817 is 71891002.

Together with previous prime (20019781) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18071001 + 1948816 = 4251^2 + 1396^2 .

It is a cyclic number.

It is not a de Polignac number, because 20019817 - 2¹¹ = 20017769 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20019827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10009908 + 10009909.

It is an arithmetic number, because the mean of its divisors is an integer number (10009909).

Almost surely, 2^20019817 is an apocalyptic number.

It is an amenable number.

20019817 is a deficient number, since it is larger than the sum of its proper divisors (1).

20019817 is an equidigital number, since it uses as much as digits as its factorization.

20019817 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 20019817 is about 4474.3510143930. The cubic root of 20019817 is about 271.5313847548.

The spelling of 20019817 in words is "twenty million, nineteen thousand, eight hundred seventeen".